Mask seal



FIG. 1 is a front perspective view of a mask seal;

FIG. 2 is a back perspective view of a mask seal;

FIG. 3 is a front perspective view of a mask seal;

FIG. 4 is a back perspective view of a mask seal;

FIG. 5 is a front elevation view of a mask seal;

FIG. 6 is a back elevation view of a mask seal;

FIG. 7 is a right side elevation view of a mask seal, the left side being a mirror image;

FIG. 8 is a cross-sectional view of a mask seal taken on line 8-8, FIG. 5;

FIG. 9 is a top plan view of a mask seal; and,

FIG. 10 is a bottom plan view of a mask seal.

The broken line showing of a mask in FIGS. 1 and 2 is included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM The ornamental design for a mask seal, as shown and described. 